Name the causative organism for syphilis.

Explanation

### Step-by-Step Solution:

1. **Identify the Disease**: The question asks for the causative organism of syphilis. Syphilis is a well-known venereal disease, also classified as a sexually transmitted disease (STD).

2. **Understand Transmission**: Syphilis is transmitted primarily through sexual intercourse, which involves the exchange of bodily fluids.

3. **Identify the Causative Organism**: The specific organism that causes syphilis is a bacterium.

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